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Acetylcholinesterase (AChE) activity at the synapses of presynaptic boutons on presumed alpha-motoneurons in the chicken ventral horn was studied histochemically at the light- and electron-microscope levels. At the light-microscope level, many dot-like AChE-active sites were observed on the soma and dendrites of presumed alpha-motoneurons. On electron(More)
Gastrin-releasing peptide (GRP) has recently been identified as an itch-specific neuropeptide in the spinal sensory system in mice, but there are no reports of the expression and distribution of GRP in the trigeminal sensory system in mammals. We characterized and compared GRP-immunoreactive (ir) neurons in the trigeminal ganglion (TG) with those in the rat(More)
The brain is considered to be a target site of peripheral steroid hormones. In contrast to this classical concept, new findings over the past decade have established that the brain itself also synthesizes steroids de novo from cholesterol through mechanisms at least partly independent of peripheral steroidogenic glands. Such steroids synthesized de novo in(More)
Previous studies on polytocous rodents have revealed that the fetal intrauterine position influences its later anatomy, physiology, reproductive performance and behavior. To investigate whether the position of a fetus in the uterus modifies the development of the brain, we examined whether the structure of the sexually dimorphic nucleus of the preoptic area(More)
Neurosteroids are synthesized de novo in the brain, and the cerebellar Purkinje cell is a major site for neurosteroid formation. We have demonstrated that the Purkinje cell possesses intranuclear receptor for progesterone and actively produces progesterone de novo from cholesterol only during rat neonatal life, when cerebellar cortical formation occurs(More)
The cerebellar Purkinje cell (PC) is a typical site for neurosteroid formation. We have demonstrated that this neuron possesses intranuclear receptor for progesterone and actively synthesizes progesterone de novo from cholesterol only during rat neonatal life, when the formation of the cerebellar cortex occurs dramatically. In this study, we therefore(More)
Neurosteroids are synthesized de novo from cholesterol in the brain. To understand neurosteroid action in the brain, data on the regio- and temporal-specific synthesis of neurosteroids are needed. Recently, we identified the Purkinje cell as an active neurosteroidogenic cell. In rodents, this neuron actively produces several neurosteroids including(More)
The cerebellar Purkinje cell is a major site for neurosteroid formation. We have demonstrated recently that the Purkinje cell actively produces sex steroids, such as estradiol and progesterone, de novo from cholesterol only during rat neonatal life, when cerebellar cortical formation occurs. We have further demonstrated that both estradiol and progesterone(More)
Circulating levels of androgens determine the sexual differentiation of the brain and spinal cord at a critical period. Although estradiol, which is converted from testosterone by aromatase action, can explain the cytological basis for the sexual dimorphism, androgen has its own regulatory mechanism to promote male-specific behavior through receptors. The(More)
Peripheral steroid hormones act on brain tissues through intracellular receptor-mediated mechanisms to regulate several important brain neuronal functions. The brain is therefore considered to be a target site of steroid hormones. In contrast to this classical concept, new findings over the past decade have established that the brain itself also synthesizes(More)